Caution: Translations of Quran and Ḥadīth may lead to possible misapplications and misinterpretations. This site is intended for students of sacred knowledge that are proficient in comprehending classical Arabic and have a strong foundation in Islamic sciences. Also note that religious injunctions rely on several aspects beyond what one may glean through reading individual aḥādīth.
ahmad:22530Sufyān > Samiʿnāh from Dāwud b. Shābūr > Abū Qazʿah > Abū al-Khalīl > Abū Ḥarmalah > Abū Qatādah

[Machine] Fasting on Arafah expiates the sins of the year, as well as the year that follows it. Fasting on Ashura expiates one year of sins. Abdullah said, my father did not recommend it to us, and it is a recommended act.  

أحمد:٢٢٥٣٠حَدَّثَنَا سُفْيَانُ قَالَ سَمِعْنَاهُ مِنْ دَاوُدَ بْنِ شَابُورَ عَنْ أَبِي قَزْعَةَ عَنْ أَبِي الْخَلِيلِ عَنْ أَبِي حَرْمَلَةَ عَنْ أَبِي قَتَادَةَ قَالَ

صِيَامُ عَرَفَةَ يُكَفِّرُ السَّنَةَ وَالَّتِي تَلِيهَا وَصِيَامُ عَاشُورَاءَ يُكَفِّرُ سَنَةً قَالَ عَبْدُ اللهِ قَالَ أَبِي لَمْ يَرْفَعْهُ لَنَا سُفْيَانُ وَهُوَ مَرْفُوعٌ